Indexing Driving Device of a Turntable

ABSTRACT

The present invention provides an indexing driving device for a turntable, which is provided with a plurality of roller followers arranged at equal angular intervals; and a barrel component, which is provided on one side of the turntable, the cam component is provided with a first side rib wall with a continuous cam curved surface in a first direction and a second side rib wall with a continuous cam curved surface in a second direction, and the first side rib wall and the second side rib wall are facing opposite sides to form a cam groove with variable groove width, for introducing the roller followers and rotating the turntable; wherein the cam groove with variable groove width makes the first side rib wall and the second side rib wall respectively pre-compress to at least one pair of the roller followers of the turntable symmetrically in different directions, so as to effectively eliminate the backlash problem between the cam component and the roller followers and improve the positioning accuracy of the turntable.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 106141410 filed in Taiwan, Republic ofChina, on Nov. 28, 2017, the entire contents of which are herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention especially related to an indexing driving device,which can eliminate the backlash between cam components and rollerfollowers, to avoid the shock and vibration so as to increase thepositioning accuracy of the turntable.

BACKGROUND OF THE INVENTION

The roller type turntable is widely used in the indexing application ofthe machine tool, such as the indexing plate of the fourth axis or thecutter head of the tool magazine; in general, based on the position ofthe roller follower, the indexing driving mode of the roller typeturntable can be divided into drive mode of roller gear cam drive modeand drive mode of barrel cam, so as to position the turntable in apreset position. Please refer to FIG. 1, which shows the so-called drivemode of roller gear cam, wherein the roller follower 10 is provided onthe outer circumference of the turntable 11, and the central axis ofeach roller follower 10 is vertically radiated. The roller gear cam 12drives the roller follower 10 on the outer circumference of theturntable 11, thereby drives the turntable 11 to rotate and bepositioned at a preset position. Please refer to FIG. 2, which isso-called drive mode of barrel cam, the roller follower 20 is providedon the disk surface of the turntable 21, and the center axis of each ofthe roller follower 20 is parallel to the central axis of the turntable21, and the barrel cam 22 drives the roller follower 20 on the disksurface of the turntable 21, thereby drives the turntable 21 to rotateand be positioned at a preset position.

However, whether the roller gear cam or the barrel cam drives the drivenroller of the turntable, the roller follower can only contact the ribwall on the cam side and make a rolling contact. There must be a gapbetween the cam groove of the roller gear cam or the barrel cam and theroller followers. When the gap is driven, the roller follower and therib wall on the other side will make a so-called backlash. Generally,the backlash is about 0.1 m. Please refer to FIG. 2, as for the barrelcam, the roller follower 20 on the disk surface of the turntable 21 mustbe rolling contact on at least one side of the cam groove 221 of thebarrel cam 22, and the roller follower 20 must also be rotatable in thecam groove 221.

Therefore, the groove width of the cam groove 221 of the barrel cam 22must be slightly larger than the outer diameter of the roller follower20. The cam groove 221 of the barrel cam 22 is conventionallymanufactured by the outer diameter of the roller follower 20 plus therequired groove width of the cam groove 221 for rotation. The cam groove221 of the equal groove width is formed according to the required groovewidth. Therefore, when the roller follower 20 is placed in the camgroove 221, a gap is formed between the left rib wall 222 and the rightrib wall 223. Please refer to FIG. 3, when the barrel cam 22 rotatescounterclockwise (CCW), the right rib of the barrel cam 22. The wall 223will contact the pre-compressed roller followers 20 to drive theturntable 21 to rotate clockwise (CW), but the respective rollerfollower 20 and the left rib wall 222 of the barrel cam 22 are alsoproduced a backlash with 0.1 mm width. In contrast, please refer to FIG.4, when the barrel cam 22 rotates clockwise (CW), the left side rib wall222 of the barrel cam 22 will contact and pre-compress to each of theroller follower 20, to rotate the turntable 21 counterclockwise (CCW).Whereas each of the roller follower 20 and the barrel cam 22 of theright side wall of the rib 223 has also produced a backlash with 0.1 mmwidth. The existence of the backlash mentioned above not only causes theshock and vibration between the rib wall and the roller follower of thecam when the barrel cam is started or reversed, but also affects thepositioning accuracy of the index rotation of the turntable. Inparticular, the rotation of the indexing disc of the fourth shaftaffects the machining accuracy of the workpiece, so whether it is thedriving method of roller gear cam or driving method of barrel cam, themanufacturer is working to eliminate the backlash design.

Please refer to FIG. 1, due to the radial force generated by therotation of the roller gear cam 12 driving the turntable 11 intersectsthe center axis of the turntable 11, the driving method of roller gearcam is known to utilize the inclined angle design on the rib wall 121 ofthe roller gear cam 12, and adjust the axial distance between theturntable 11 and the roller gear cam 12, the backlash between the rollergear cam 12 and the roller follower 10 can be eliminated. However, sucha method changes the axial distance between the turntable 11 and theroller gear cam 12, so it will change the motion mode set from theoriginal design, thereby causing motion errors.

Please refer to FIG. 2, as for the driving mode of barrel cam, theradial force generated by the rotation of the barrel cam 22 driving theturntable 21 is parallel to the central axis of the turntable 21. If theaxial distance between the turntable 21 and the barrel cam 22 isadjusted, not only the turntable 21 would to be unilaterally forced thensway and skew, but also the original designed motion mode would bechanged, thereby causing motion errors. Regardless the driving mode ofroller gear cam or the barrel cam, the existing problem of backlashcannot be effectively solved.

In view of this, the inventor has been engaged in research anddevelopment and production of related industries for many years, and hasconducted in-depth research on the problems currently faced. Afterlong-term efforts and research, the inventor has finally developed aneffective elimination the problem of backlash between cam components androller followers. The shortcomings of the prior art is improvedeffectively, which is the design tenet of the present invention.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide an indexingdriving device of turntable, which is provided with a plurality ofroller followers arranged at equal angular intervals; and a barrelcomponent, which is provided on one side of the turntable, the camcomponent is provided with a first side rib wall with a continuous camcurved surface in a first direction and a second side rib wall with acontinuous cam curved surface in a second direction, and the first siderib wall and the second side rib wall are facing opposite sides to forma cam groove with variable groove width, for introducing the rollerfollowers and rotating the turntable; wherein the cam groove withvariable groove width makes the first side rib wall and the second siderib wall respectively pre-compress on at least one pair of the rollerfollowers of the turntable symmetrically in different directions, so asto effectively eliminate the backlash problem between the cam componentand the roller followers.

The second object of the present invention is to provide an indexingdriving device for a turntable, wherein the first side rib wall and thesecond side rib wall are respectively pre-compress to at least one pairof roller followers symmetrically in different directions. In order toeliminate the backlash between the cam component and the rollerfollowers, the shock and vibration between the cam component and eachroller follower can be effectively avoided whether in the forward orreverse start or stop, thereby effectively reducing noise and vibrationduring transmission.

The third object of the present invention is to provide an indexingdriving device for a turntable, wherein the first side rib wall and thesecond side rib wall respectively pre-compress to at least one pair ofroller followers of the turntable by different directions. In order toeliminate the backlash between the cam component and the rollerfollowers, the turntable can be accurately positioned at the presetposition when the cam component is rotated and positioned, therebyeffectively improving the positioning accuracy of the turntable.

The fourth object of the present invention is to provide an indexingdriving device for a turntable, wherein the first side rib wall and thesecond side rib wall are respectively pre-compress to at least one pairof roller followers symmetrically in different directions. In order toeliminate the backlash between the cam component and the rollerfollowers, the turntable can be accurately positioned at the presetposition when the cam component is rotated and positioned, therebyeffectively improving the machining accuracy of the working piece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Schematic diagram of the driving mode of conventional rollergear cam.

FIG. 2: Schematic diagram of the driving mode of conventional barrelcam.

FIG. 3: Figure shows the relative positional relationship diagram of theleft and right rib walls of each roller followers, when the barrel camof FIG. 2 is rotated counterclockwise.

FIG. 4: Shows the relative positional relationship diagram of the leftand right rib walls of each roller followers, when the barrel cam ofFIG. 2 is rotated clockwise

The relative positional relationship diagram of the left and right ribwalls of the wheel.

FIG. 5: Schematic diagram of the structure of the present invention.

FIG. 6: Schematic diagram of the cam component in the present invention.

FIG. 7: Schematic view showing the roller follower is placed in the camcomplement of the present invention.

FIG. 8: Schematic diagram shows the relative positional relationshipbetween each of the roller follower and the first and second side ribwalls of the cam component in FIG. 7.

FIG. 9: Schematic diagram shows the counterclockwise rotation of the camcomponent of the present invention.

FIG. 10: Schematic diagram shows the cam component of the presentinvention rotated 360 degrees counterclockwise.

FIG. 11: Schematic diagram shows the relative positional relationshipbetween each of the roller follower and the first and second side ribwalls of the cam component in FIG. 10.

FIG. 12: Schematic diagram shows the clockwise rotation of the cammember of the present invention.

FIG. 13: Schematic diagram shows the cam member of the present inventionrotated 360 degrees clockwise.

FIG. 14: Schematic diagram shows the relative positional relationshipbetween each of the roller follower and the first and second side ribwalls of the cam component in FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

In order to let the reviewer further understand the present invention,the preferred embodiment will be described in detail as the followingdescription:

Please refer to FIG. 5, the driving mode of present invention can beroller gear cam and barrel cam; in one of the embodiments of the presentinvention, the barrel cam is used as driving mode for description; inthe driving mode of barrel cam, the turntable 31 is provided on amachine base 30, the turntable 31 is freely rotatable on the machinebase 30, the turntable 31 is having a plurality of roller followers 32arranged at equal angular intervals.

In one of the embodiments of the present invention, the turntable 31 ishaving 20 roller followers 32 arranged at equal angular intervals. Thecentral axis of the plurality of roller followers are parallel to thecentral axis of the turntable, and the cam component is barrel cam. Abarrel component 40 is provided on one side of the turntable 31. In oneof the embodiments of the present invention, the cam component 40 isbarrel cam, wherein the cam component 40 is having a cam axle 41, oneend of the cam axle 41 is connected to a driving source 50 to drive thecam component 40 to rotate. The driving source 50 of the cam component40 is connected to a reducer 51, the reducer is driving connected to thecam axle 41 of the can component 40.

Please refer to FIG. 6, the cam component 40 is provided with a firstside rib wall 42 with a continuous cam curved surface in a firstdirection and a second side rib wall 43 with a continuous cam curvedsurface in a second direction, and the first side rib wall 42 and thesecond side rib wall 43 are facing opposite sides to form a cam groovewith “variable groove width”, for introducing the roller followers 32and rotating the turntable 31; Besides, the leading end of the firstside rib wall 42 and the second side rib wall 43 of the cam componentextends with a progressive guiding can curved surface 421, 431 forprogressively leading or introducing the rollers followers 32 smoothly.In one of the embodiments of the present invention, the cam component 40is designed according to various conditions, and the can component 40 isprovided with a first side rib wall 42 with a continuous cam curvedsurface in a first direction (from right to left) formed by machining,and the cam component 40 is provided with a second side rib wall 43 witha continuous cam curved surface in a second direction (from left toright) formed by machining to form a cam groove with “variable groovewidth”. That is, the conventional technology first constructs the cangroove, and the first side rib wall and the second side rib wall arenaturally formed on the two sides of the cam groove, so that the “equalgroove width” of can groove is obtained. However, the invention firstlyconstructs a continuous cam curved surface of the first side rib wall 42and the second side rib wall 43, so that the cam groove with “variablegroove width” can be obtained between the first side rib wall 42 and thesecond side rib wall 43.

Please refer to FIG. 7, when the cam groove 44 of the cam component 40of the present invention is placed in the roller follower of theturntable 31, since the cam groove 44 is designed to be “variable groovewidth”, the cam groove with variable groove width makes the first siderib wall 42 and the second side rib wall 43 respectively pre-stress onat least one pair of the roller followers of the turntable 31symmetrically in different directions. In one embodiment of the presentinvention, the first side rib wall 42 and the second side rib wall 43are pre-compressed by the first and second directions respectively, thefirst pair of roller followers 32 b, 32 o and the second pair of rollerfollowers 32 d, 32 e. The center position of roller follower 32 amaintains a gap with the first side rib wall 42 and the second side ribwall 43 without contact. Please refer to FIG. 8 for the relativepositional relationship between each of the roller followers 32 a, 32 b,32 c, 32 d, and 32 e and the first side rib wall 42 and the second siderib wall 43. The A1 section represents the pre-compression zone of thefirst side rib wall 42, the A2 section represents the pre-compressionimport and export area of the first side rib wall 42, and the B1 sectionrepresents the pre-compression zone of the second side rib wall 43. TheB2 section indicates the pre-compression import and export area of thesecond side rib wall 43, and the C section indicates the pre-compressionreversing area.

In the present invention, since the cam groove 44 has a design of“variable groove width”, it can be found from the relative positionalrelationship diagram that the roller follower 32 a located in thepre-compression reversing zone of the C section does not contact thefirst side rib wall 42 and the second side rib wall 43. The first pairof roller followers 32 b and the second pair of roller followers 32 dare located in the pre-compression zone of the first side rib wall 42 inthe A1 section, and the gap between the first side rib wall 42 is 0 mm;that is, the first pair of roller followers 32 b and the second pair ofroller followers 32 d are in contact with the first side rib wall 42,and are pre-compressed by the first side rib wall 42. As for the firstpair of roller followers 320 and the second pair of roller followers 32e are fall in the pre-compression zone of the second side rib wall 43 ofthe B1 section, and the gap between the second side rib walls 43 is 0mm; that is, the first pair of roller followers 32 c and the second pairof roller followers 32 e are in contact with the second side rib wall 43and are pre-compressed by the second side rib wall 43, so that the firstside rib wall 42 and the second side rib wall 43 can be symmetricallypre-compressed from different directions respectively with the firstpair of roller followers 32 b, 320 and the second pair of rollerfollowers 32 d, 32 e.

Please refer to FIG. 9, when the cam component 40 is rotatedcounterclockwise (CCW), the second side rib wall 43 pre-compresses tothe first pair of roller followers 32 o and the second pair of rollerfollowers 32 e. Therefore, the second side rib wall 43 of the camcomponent 40 can be used to immediately move the first pair of rollerfollowers 32 c and the second pair of roller followers 32 e to drive theturntable 31 clockwise (CW) to rotate, and effectively avoid the impactbetween the can component 40 and each of the roller followers, therebyeffectively reducing the noise and vibration of the transmission. Pleaserefer to FIGS. 10 and 11, after the cam component 40 is rotated 360degrees counterclockwise (CCW), the guiding cam curved surface 431 ofthe leading end of the second side rib wall 43 of the cam component 40can be gradually derived from the pre-compression import and export areaof the second side rib wall 43 of the B2 section, so that thepre-compression zone of the second side rib wall 43 of the B1 section ischanged to pre-compresses on the roller followers 320, 32 a. Meanwhile,the rotation of the turntable 31 is also synchronized with the rollerfollower 32 b to the pre-compression reversing zone of the C sectionwithout contacting the first side rib wall 42 and the second side ribwall 43, and the roller follower 32 d is maintained in the first siderib of the A1 section. The pre-compression zone of the first side ribwall 42 and the guiding cam surface 421 of the leading end of the firstside rib wall 42 are progressively introduced into the roller follower32 f from the pre-compression import and export area of the first siderib wall 42 of the A2 section, and the roller follower 32 f enters thepre-compression zone of the first side rib wall 42 of the A1 section,and is in contact with the first side rib wall 42. The first side ribwall 42 and the second side rib wall 43 can be symmetricallypre-compressed from different directions respectively with the firstpair of roller followers 32 d, 32 a and the second pair of rollerfollowers 32 f, 32 c. Therefore, when the cam member 40 stops rotating,the roller followers 32 d, 32 f also simultaneously causes the turntable31 to stop rotating immediately, so that the turntable 31 is accuratelypositioned at the preset indexing position.

Please refer to FIG. 12, which is continued from the state of FIG. 10,when the cam component 40 is rotated clockwise (CW), the first side ribwall 42 pre-compresses to the first pair of roller followers 32 d andthe second pair of roller followers 32 f. Therefore, the first side ribwall 42 of the cam component 40 can be used to immediately move thefirst pair of roller followers 32 d and the second pair of rollerfollowers 32 f to drive the turntable 31 counterclockwise (CCW) torotate, and effectively avoid the impact between the cam component 40and each of the roller followers, thereby effectively reducing the noiseand vibration of the transmission. Please refer to FIGS. 13 and 14,after the cam component 40 is rotated 360 degrees clockwise (CCW), theguiding cam curved surface 421 of the leading end of the first side ribwall 42 of the cam component 40 can be gradually derived from thepre-compression import and export area of the first side rib wall 42 ofthe A2 section, so that the pre-compression zone of the first side ribwall 42 of the A1 section is changed to pre-compress on the rollerfollowers 32 b, 32 d. Meanwhile, the rotation of the turntable 31 isalso synchronized with the roller follower 32 c to the pre-compressionreversing zone of the C section without contacting the first side ribwall 42 and the second side rib wall 43, and the roller follower 32 c ismaintained in the second side rib of the B1 section. The pre-compressionzone of the second side rib wall 43 and the guiding cam surface 431 ofthe leading end of the second side rib wall 43 are progressivelyintroduced into the roller follower 32 e from the pre-compression importand export area of the second side rib wall 43 of the B2 section, andthe roller follower 32 e enters the pre-compression zone of the secondside rib wall 43 of the B1 section, and is in contact with the secondside rib wall 43. The first side rib wall 42 and the second side ribwall 43 can be symmetrically pre-compressed from different directionsrespectively with the first pair of roller followers 32 b, 32 c and thesecond pair of roller followers 32 d, 32 e. Therefore, when the cammember 40 stops rotating, the roller followers 32 c, 32 e alsosimultaneously causes the turntable 31 to stop rotating immediately, sothat the turntable 31 is accurately positioned at the preset indexingposition.

According to the above description, the can component provides thedesign of the cam groove with “variable groove width”. Therefore, thecam component can pre-compress to at least one pair of roller followerson the first side rib wall with a continuous cam curved surface in afirst direction and on the second side rib wall with a continuous camcurved surface in a second direction, so as to keep the zero backlashstate between the first side rib wall, the second side rib wall and atleast one pair of roller followers. The cam component can be positivelyor reversely started or stopped at any angular position without causingimpact vibration between the rib wall and the roller followers, whichnot only makes the turntable accurately located at the preset indexingposition and ensures the machining accuracy of the workpiece on theturntable.

Accordingly, the present invention is a practical and progressivedesign, but it has not been disclosed that the same products andpublications are disclosed, thereby permitting the invention patentapplication requirements, and applying in accordance with the law.

Although the present invention has been described in terms of specificexemplary embodiments and examples, it will be appreciated that theembodiments disclosed herein are for illustrative purposes only andvarious modifications and alterations might be made by those skilled inthe art without departing from the spirit and scope of the invention asset forth in the following claims.

SYMBOLS

The Prior Art:

-   10 roller follower-   11 turntable-   12 roller gear cam-   121 roller gear cam-   20 roller follower-   21 turntable-   22 barrel cam-   221 cam groove-   222 left rib wall-   223 right rib wall

The present invention:

-   30 machine base-   31 turntable-   32 roller follower-   32 a roller follower-   32 b roller follower-   32 o roller follower-   32 d roller follower-   32 e roller follower-   32 f roller follower-   40 can component-   41 cam axle-   42 first side rib wall-   421 guiding cam curved surface-   43 second side rib wall-   431 guiding cam surface-   44 cam groove-   50 driving source-   51 reducer-   A1 section: pre-compression zone of the first side rib wall-   A2 section: pre-compression import and export area of the first side    rib wall-   B1 section: pre-compression zone of the second side rib wall-   B2 section: pre-compression import and export area of the second    side rib wall-   C section: pre-compression reversing area

What is claimed is:
 1. An indexing driving device of turntable, whichincludes: a machine base; a turntable, which is provided on the machinebase, and the turntable is having-a plurality of roller followersarranged at equal angular intervals; a cam component, which is providedon one side of the turntable, the cam component is provided with a firstside rib wall with a continuous cam curved surface in a first directionand a second side rib wall with a continuous cam curved surface in asecond direction, and the first side rib wall and the second side ribwall are facing opposite sides to form a cam groove with variable groovewidth, for introducing the roller followers and rotating the turntable;wherein the cam groove with variable groove width makes the first siderib wall and the second side rib wall respectively pre-compress to atleast one pair of the roller followers of the turntable symmetrically indifferent directions.
 2. The indexing drive device of turntableaccording of claim 1, wherein the turntable is provided with a pluralityof roller followers on the turntable surface, and the central axis ofthe plurality of roller followers are parallel to the central axis ofthe turntable, and the cam component is barrel cam.
 3. The indexingdrive device of turntable according of claim 1, wherein the camcomponent is having a cam axle, one end of the cam axle is connected toa driving source to drive the cam component to rotate.
 4. The indexingdrive device of turntable according of claim 3, wherein the drivingsource of the cam component is connected to a reducer, the reducer isdriving connected to the cam axle of the cam component.
 5. The indexingdrive device of turntable according of claim 1, wherein the camcomponent is provided with a first side rib wall with a continuous camcurved surface in a first direction formed by machining, and a secondside rib wall with a continuous cam curved surface in a second directionformed by machining.
 6. The indexing drive device of turntable accordingof claim 1, a leading end of the first side rib wall of the camcomponent extends with a progressive guiding cam curved surface forprogressively leading or introducing the rollers followers.
 7. Theindexing drive device of turntable according of claim 1, a leading endof the second side rib wall of the cam component extends with aprogressive guiding cam curved surface for progressively leading orintroducing the rollers followers.